I have an Ariston 27MFFI. Problem at moment is if I turn on a hot tap, the boiler does not always fire up. To make it work, I have to go to the sink that is right next to the boiler and turn that hot tap on at the same time. Once boiler fires, I turn that tap off and water flows to the other. I have already replaced the differential valve as the old one was split. Any ideas?
Combi not firing up on HW demand
- Thread starter irose
- Start date
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It was the left hand one I replaced as definately had a split in it. Unfortunately, hasn't resolved the problem.
There is definitely something wrong in the Mainflow Switch area ( I think this is the one you are referring to on the front) as it does not trigger at all. I've inspected it and can't see anything wrong with the diaphram.
If I short out the reed switch on the Mainflow Switch I only get to the state of my original problem. Without shorting it out, it won't fire up at all.
If the Main flow switch itself is ok, what else could it be?
I'm wondering if I have a restriction in one if the smaller pipes as another problem is the boiler reaches max temp and cuts out, cools down and lights up again constantly. On for say 1min, off for 1 min, back on again. Absolute pain for running a bath as flow at tap has to be a trickle to average out a good temperature!
I know its time for a new boiler but money too tight at mo
There is definitely something wrong in the Mainflow Switch area ( I think this is the one you are referring to on the front) as it does not trigger at all. I've inspected it and can't see anything wrong with the diaphram.
If I short out the reed switch on the Mainflow Switch I only get to the state of my original problem. Without shorting it out, it won't fire up at all.
If the Main flow switch itself is ok, what else could it be?
I'm wondering if I have a restriction in one if the smaller pipes as another problem is the boiler reaches max temp and cuts out, cools down and lights up again constantly. On for say 1min, off for 1 min, back on again. Absolute pain for running a bath as flow at tap has to be a trickle to average out a good temperature!
I know its time for a new boiler but money too tight at mo
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Perhaps the plate heat exchnager is blocked - this would cause the hot water cycling and would restrict flow - preventing the reed switch from operating.
Also be aware the reed switches are not always soldered in the correct orientation (even new ones!) so although the diapragm and magnet could be working OK the reed may still not close.
Also be aware the reed switches are not always soldered in the correct orientation (even new ones!) so although the diapragm and magnet could be working OK the reed may still not close.
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